bullet: don't request Shaders lib in CMakeLists.
bullet: don't request Shaders lib in CMakeLists.

It is not used in the code itself and the FindMagnum.cmake now properly
handles all dependencies, so it's not needed to specifiy it explicitly.

mosra/magnum-examples,mosra/magnum-examples,mosra/magnum-examples,mosra/magnum-examples,mosra/magnum-examples,Squareys/magnum-examples,Squareys/magnum-examples,mosra/magnum-examples,Squareys/magnum-examples,mosra/magnum-examples,Squareys/magnum-examples